January 2018
Beginner to intermediate
234 pages
7h 8m
Chinese
Content preview from Kafka权威指南
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管理
Kafka
｜
157
parse.key
如果被设为 false，那么生成消息的键总是 null，默认为 true。
key.separator
指定消息键和消息值之间的分隔符，默认是
Tab
字符。
在生成消息时，
LineMessageReader
使用第一个出现的 key.separator 作为分隔符来拆分输
入。如果在分隔符之后没有其他字符，那么消息的值为空。如果输入里没有包含分隔符，
或者
parse.key
被设为
false
，那么消息的键就是
null
。
9.6
客户端
ACL
命令行工具
kafka-acls.sh
可以用于处理与客户端访问控制相关的问题，它的文档可以在
Apache Kafka
官方网站上找到。
9.7
不安全的操作
有一些管理操作虽然在技术上是可行的，但如果不是非常有必要，就不应该尝试那么做。
比如，你正在诊断一个问题，但已经没有其他可行的办法，或者发现了一个
bug
，需要一
个临时解决方案。这些操作一般在文档里不会有相关的说明，而且未经证实，有可能会给
应用程序带来风险。
这里会列举一些常见的操作，在紧急情况下可以使用它们。不过，一般情况下不建议执行
这些操作，而且在执行之前要慎重考虑。
此处有危险
本节介绍的操作将涉及保存在
Zookeeper
上的元数据。除了这里提到的内容
以外，不要直接修改
Zookeeper
的其他任何信息，一定要小心谨慎，因为这
些操作都是很危险的。
9.7.1
移动集群控制器
每个
Kafka
集群都有一个控制器，它是运行在集群某个
broker
上的一个线程。控制器负责
看管集群的操作，有时候需要将控制器从一个 ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.